Tens of thousands of people took part in anti-austerity demonstrations in cities across Britain on Saturday.

Joined by some union leaders and celebrities, the largest march was in London, where thousands of people gathered outside the Bank of England and later walked to the House of Parliament.

The national demonstration End Austerity Now was organized by the People's Assembly, a group who said it is a broad united national campaign against austerity, cuts and privatization in workplaces, community and welfare services.

The demonstration started at noon on Saturday. Beside London, anti-austerity protests also occurred in other cities, including Liverpool, Glasgow and Bristol, media reports said.

About 250,000 people attended the protests on Saturday, according to the organizer.

Most of the protests went peaceful, with a handful of fires and smoke bombs set off, but no serious violence was reported, according to The Guardian.

Rally leaders addressed the crowds, and strongly attacked the austerity policy carried out by current government.

Demonstrations on Saturday were the first major public protests since British Prime Minister David Cameron won the election last month.